(1) Field of the Invention
The invention relates to the use of stevensite or stevensite-containing components for adsorption of toxins, especially mycotoxins, to a process for improving the utilizability of mycotoxin-contaminated foods or animal feeds, and a food or animal feed formulation comprising a stevensite-containing mycotoxin adsorbent.
(2) Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
The term “mycotoxins” encompasses a group of toxic substances which are formed by different naturally occurring fungi. Currently about 300 to 400 mycotoxins are known. The natural habitat of these fungi is considered to be cereal species and cereal grains in general. While some fungal types develop actually on the cereal grain as it is still maturing on the ear, other types principally infest stored cereal animal feed stocks when there is a certain minimum moisture content and ambient temperature.
All so-called mycotoxins have a harmful effect on health primarily on agricultural livestock fed with contaminated cereal types, but secondarily also on the human via the food chain.
Globally, principally the following mycotoxins are of significance with different regional emphasis in animal but also human nutrition: aflatoxin, ochratoxin, fumonisin, zearalenone, deoxynivalenol, T-2 toxin and ergotamine. For further discussion of these and further mycotoxins, reference may be made to WO 00/41806 to the same applicant and the references cited there.
As a result of the development of more sensitive analysis methods, it has been possible to determine, in various animal feeds, several different toxins which have been recognized as a cause of health problems in humans and animals. A series of studies have shown that several toxins can occur simultaneously, for example in animal feeds. This simultaneous occurrence can considerably influence the toxicity of the mycotoxins. In addition to acute damage to livestock which receive mycotoxin-contaminated animal feed, the literature has also discussed health damage to humans, which arises through consumption over a prolonged period of foods slightly contaminated with mycotoxins.
In a more recent analysis of suspect feed samples, aflatoxin, deoxynivalenol or fumonisin were found in over 70% of the samples analyzed (cf. “Understanding and coping with effects of mycotoxins in life dog feed and forage”, North Carolina Cooperative Extension Service, North Carolina State Univ.).
In many cases, the economic effects in relation to reduced productivity of the animals, increased occurrence of diseases as a result of immunosuppression, damage to vital organs, and the impairment of reproductivity are more significant than the effects caused by the death of animals as a result of mycotoxin poisoning.
The group of the aflatoxins, owing to its specific molecular structure, is fixed with high specificity on some mineral adsorbents, for example zeolite, bentonite, aluminum silicate and others (cf. A.-J. Ramos, J. Fink-Gremmels, E. Hernandez, “Prevention of Toxic Effects of Mycotoxins by Means of Nonnutritive Adsorbent Compounds”, J. of Food Protection, Vol. 59(6), 1996, p. 631-641).
For instance, U.S. Pat. No. 5,149,549 describes and claims the use of bentonite as a mycotoxin adsorbent, but especially an aflatoxin adsorbent, for use in animal feed.
However, the other important mycotoxins listed above are bound to natural mineral adsorbents with only very low effectiveness. In order to improve the adsorption capacity of mineral adsorbents for these non-aflatoxins, various types of surface modifications on natural sheet silicates have been proposed.
S. L. Lemke, P. G. Grant and T. D. Phillips describe, in “Adsorption of Zearalenone by Organophilic Montmorillonite Clay”, J. Agric. Food Chem. (1998), p. 3789-3796, an organically modified (organophilic) montmorillonite clay which is capable of adsorbing zearalenone. The use of organically modified sheet silicates or mixtures of organically modified and unmodified sheet silicates is also known from EP 1 150 767 B1 to the same applicant.
However, what is common to the organically modified (organophilic) adsorbents is that they bind only a selection of certain toxins with high effectiveness, while other toxins, for example fumonisin, cannot be bound effectively even as a result of an organophilic surface modification. In addition, the organophilic modification of the sheet silicates is complicated and hence costly.
The use of acid-activated sheet silicates is known from EP 1 333 919 B1 to the same applicant. Although this acid activation enhances the adsorption performance for toxins which can be bound particularly to acidic surfaces (for example fumonisin), the capability of binding other toxins is reduced. Acid activation, like other modifications to the sheet silicates too, is also a complicated and therefore expensive process. The costs of the mycotoxin adsorbent are a significant argument especially in the case of use in the animal feed industry.